THE SCIENTIFIC SPIRIT IN ENGLAND. 



241 



Fourier's great work on the theory of heat, which for the 

 first time propounded a universal method applicable to 

 the mathematical treatment of almost every physical 

 problem, inasmuch as it, so to speak, follows nature into 

 the marvellous composition of the many movements out 

 of which all her phenomena are compounded, lay buried 

 for fourteen years in the archives of the Institute. That 

 great authority had failed to recognise its paramount 

 importance.^ Fresnel's first memoir, which estabhshed 

 on a firm mathematical basis the undulatory theory of 

 light, was for years left unpublished, whilst the whole 

 scientific world was anxiously expecting the results of 

 his inquiries.^ In Germany we have examples of similar 



12. 

 Fourier. 



^ Jean Bapt. Jos. Fourier (1768- 

 1830), of humble origin, in his 

 celebrated ' Theorie aualytique de 

 la Chaleur' (Paris, 1822), and in 

 previous memoirs, carried further 

 the mathematical treatment of phy- 

 sical phenomena and introduced 

 wider conceptions of mathematical 

 quantities and their dependence 

 i.e., of a mathematical "function." 

 His investigations have led to far- 

 reaching applications in physical 

 science (Ohm and Lord Kelvin), 

 and to profound mathematical theo- 

 ries (Dirichlet, Riemann, &c.) The 

 so-called " Fourier " series has thus 

 a great applied as well as theoreti- 

 cal interest. Fourier's first memoir 

 was presented to the Institute in 



1807 ; an extract was published in 



1808 ; a second memoir was pre- 

 sented in 1811 and crowned, but 

 was not printed till 1824, two years 

 after the great work itself had ap- 

 peared. On the physical importance 

 of Fourier's analysis see Helm- 

 holtz, 'Vortriige und Reden,' vol. i. 

 p. 101, &c. ; Sir W. Thomson, 

 Mathematical and Physical Papers, 

 passim, but especially vol. ii. p. 41, 



VOL. L 



&c. On the purely mathematical 

 interest that attaches to the Fou- 

 rier series see especially Riemann, 

 ' Mathematische Werke,' p. 218, 

 &c. A very concise summary of 

 the history of the series is also 

 given byt George A. Gibson in the 

 'Proceedings of the Edinburgh 

 Mathematical Society,' vols. xi. and 

 xii. We shall revert to this subject 

 in a subsequent chapter. 



2 Augustin Fresnel (1788-1827) 

 divides with Thomas Young the 

 merit of having established the 

 undulatory theory of light on a 

 firm basis. His first memoir on 

 Diffraction of Light was presented 

 to the Academy in 1815, a more 

 extensive paper in 1818 ; this was 

 crowned in 1819, but not printed 

 till 1826. Other papers of his 

 were mislaid or lost. The delay 

 in bringing before the world these 

 important discoveries has been at- 

 tributed to the opposition of La- 

 place and his party in the Institute, 

 which even the influence of Arago 

 could not overcome. See what Sir 

 John Herschel says in 1827, refer- 

 ring to Fresnel's memoir of 1821 on 



Q 



13. 

 Fresnel. 



